issue #1110
state in class javadoc that null keys and values are not allowed; add javadoc to all methods that take keys or values as params and do not allow null stating an NPE is thrown for null keys or values
add missing null key/value checks to putAll() impl; remove un-needed null value check from 2-param putAsync() (4-param putAsync() will handle the check)
add a testNullChecks() test method that verifies that all IMap methods that take keys or values as params and do not allow null, throw a NullPointerException if passed a null key or value
remove undesired formatting added by IntelliJ
remove undesired formatting added by IntelliJ (take 2...)
remove NPE on null key assertions for IMap#addEntryListener() methods
Updated spy-memcached test dependency, removed its repository entry.
Updated hibernate dtd url in test resources.
Config documentation fix.
Some cleanup in the session replication:

- the debug parameter is dropped. The only thing it does is change the loglevel, but that can just as easily
be configured by setting the loglevel for the session replication. That is the traditional way to see what
is going on inside an application.

- improved logging messages

- log statements that generate new strings, are fronted with a log.islevelenabled check to prevent
unwanted stringconcatination

- some minor code cleanup
Changed loglevel for client hz instance creation to warning
Merge pull request #1117 from ispringer/feature-imap-null-values-master

improve code, javadoc, and tests relating to disallowed null keys/values
Merge pull request #1111 from ahmetmircik/fix1110

issue #1110
bug fix issue #1110
Merge pull request #1122 from ahmetmircik/fix/bug/issue1110

bug fix issue #1110
Merge pull request #1121 from pveentjer/improvement/3.x/sessionreplication-loggingcleanup

Improvement/3.x/sessionreplication loggingcleanup
Changed RemoteCallKey's caller field to callerUUID from callerAddress.
check near cache
serialization bug on MapAddEntryListenerRequest